Fruad in my account

Telkom debits different amounts in my account and I don't have a contract with them. I have nothing with them, they started debiting my account In January 2015. I app**** for a contract phone with them in October last year and I got declined to my surprise they debit my account I went back to the store and they said they are investigating a ***** case the sent a case number that was it . I went back again on Sunday ***5 and nothing was reported they then escalated the matter. Today 26/05/2015 they debited my account again. I cant get any responses from them I cant contact them their phone is always busy I am really frustrated. I went to the bank to reverse April and May amount the bank cant go as far as Feb and Jan. I really need your help.